Friday, September 9, 2011

It's correlation, not causation, and the nice, conservatively-worded article makes that clear:

"A new analysis of earlier research finds that both higher vitamin D intake and higher blood levels of the vitamin's active form are linked to lower risk of colon and rectal cancers.

"In 18 studies that included more than 10,000 people, colon cancer risk was as much as 33 percent lower in subjects with the highest blood levels of vitamin D compared to those with the lowest levels, researchers report in the Journal of Clinical Oncology. Those with the highest intake of vitamin D through supplements and food had 12 percent lower risk than those with the lowest intakes.

"The total of studies available for analysis is still sparse, noted senior author Dr. Huanlong Qin and his colleagues from The Sixth People's Hospital affiliated with Shanghai Jiao Tong University in Shanghai. Additional studies would be 'highly desirable to enable more precise estimates and a better understanding of the role of vitamin D in colorectal cancer carcinogenesis,' they write.

"Vitamin D has previously been linked to protection from various cancers, heart disease, diabetes and asthma, among other conditions. How the vitamin might exert a beneficial effect is still poorly understood, however. Some evidence suggests that to achieve a benefit people may need more than current recommended daily requirements...."